JPH04141850A - Power transmission device for magnetic recording/ reproducing device - Google Patents

Abstract

PURPOSE:To surely transmit power without a pully idling by engaging a disk having a hole engaged with a hexagonal pole formed on a pully base with the pulley base and providing a hexagonal pyramid stand on the edge surface of the hexagonal pole. CONSTITUTION:The pully base 4 having a shaft 9 transmissing the torque of a motor to the mechanism part of a magnetic recording/reproducing device and a polygonal pole 10 whose side ridge lines are parallel to the shaft, the disk 7 engaged with the polygonal pole 10 and felt 3 are provided. Furthermore, the hexagonal pyramid stand 11 which is provided with the pully 2 that is freely and rotatably fused to the pully base in a position sandwiched by the felt of the pully base and the felt of the disk and whose outer periphery is driven by a rubber belt 1, and with a spring 5 pressing the disk in the direction of the pully base, and which has an inclined plane in the hexagonal pole 10 is provided. Even if force more than the pressed force of the spring 5 is added to the pully owing to any abnormality and engagement between the disk 7 and the hexagonal pole 10 of the pully base 4 comes off, smooth engagement can be executed again. Thus, power can surely be transmitted without the pully idling.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a power transmission device for a magnetic recording/reproducing device such as a VTR.

2. Description of the Related Art A conventional magnetic recording and reproducing apparatus will be described below with reference to the drawings. 3 and 4 are detailed diagrams of the conventional technology.

A pulley base 4 is fixed to the shaft 9 in the correct size. An annular felt 3 is adhered and fixed to the pulley base 4. Further, the pulley base 4 has a hexagonal column 10 in a part thereof, and a cap 8 is fixed to the tip of the pulley base 4. The shaft hole of the pulley 2 is rotatably fitted into the pulley base 4, and the flat surface of the pulley 2 is in frictional contact with the felt 3. A hexagonal hole is provided in the center of the disk 7 to which the annular felt 6 is adhered and fixed.
It fits into the hexagonal column 10 of the pulley base 4. There is a spring 5 between the cap 8 and the disc 7, which presses the disc 7 in the direction of arrow A to create a predetermined friction between the felt 3, the felt 6, and the pulley 2. Rotational force from a motor (not shown) is transmitted by a rubber belt 1 placed around the outer periphery of the pulley 2. This rotational force is transmitted to the pulley base 4 and disk 7 by the frictional force between the pulley 2 and the felts 3 and 6, and then to the shaft 9. Although not shown, there is another gear on the shaft 9, and rotational force is transmitted from this gear to other mechanical parts of the VTR. Usually, as above,
Although the pulley 2, pulley base 4, and disc 7 are rotating at almost the same rotational speed due to the frictional force between the felts 3, 6 and the pulley 2, due to some abnormality, the load applied to the shaft 9 may exceed a predetermined value. When you cross over, use felt 3.6 and pulley 2.
As a result, rotational force exceeding a predetermined value is not transmitted to the shaft 9. This protects other mechanical parts connected to the shaft 9 from damage due to excessive rotational force.

Problems to be Solved by the Invention In the configuration of such a conventional power transmission device, if a force greater than the pressing force of the spring 5 is applied to the pulley 2 in the direction of arrow B in FIG. 3 due to some abnormality, the disc 7 also It moves in the direction of arrow B, and the hexagonal column 10 of the pulley base 4 and the hexagonal hole of the disc 7 are disengaged from each other. - If the hexagonal column 10 and the hexagonal hole of the sheet metal 7 become unfitted, they will not be able to fit with the hexagonal hole of the disc 7 or the hexagonal column 10 of the pulley base 4, as shown in FIG. 5, and the original state will not be restored. . Therefore, since the pulley 2 is not pressed against the pulley base 4, the frictional force caused by the felts 3 and 6 disappears, and the pulley 2
The engine spins idly and power cannot be transmitted.

The present invention solves the above-mentioned problem, and even if the pulley 2 moves in the direction B from the hexagonal column 10 and the hexagonal column 10 and the hexagonal hole of the disk 7 are disengaged, it will immediately return to its original state. It is an object of the present invention to provide a highly reliable power transmission device for a magnetic recording/reproducing device that can perform the following steps.

Means for Solving the Problems In order to solve the above-mentioned problems, the power transmission device of the magnetic recording and reproducing device of the present invention includes a shaft that transmits the rotational force of the motor to the mechanical section of the magnetic recording and reproducing device, and a shaft that is fixed to the shaft. a pulley base having a plane perpendicular to the shaft and a polygonal column with a side edge parallel to the shaft, a disc that fits with the polygonal column, and a felt attached to the plane part of the pulley base and the disc. and a pulley rotatably engaged with the pulley base at a position sandwiched between the felt of the pulley base and the felt 7 of the disc, and whose outer periphery is driven by a rubber belt, and the disc is connected to the pulley along the shaft. It consists of a spring that presses in the direction of the base, the rotational force of the pulley is transmitted to the shaft by the friction between the felt and the pulley due to the pressing force of the spring, and a truncated polygonal pyramid is arranged at the end of the polygonal column. It is.

Function The power transmission device of the magnetic recording and reproducing apparatus of the present invention has the above-described configuration, and a truncated polygonal pyramid is formed at the end of the polygonal column formed on the pulley base, so that force acts in the direction B, causing the disc 7 and the pulley to Even if the hexagonal column 10 of the base 4 is disengaged, it can be smoothly fitted again.

EXAMPLES Hereinafter, examples of the present invention will be described with reference to the drawings.

FIG. 1 shows the configuration of a power transmission device of a magnetic recording/reproducing apparatus according to the present invention, and most of the parts are the same as those of the conventional example, and the same numbers are used, and the explanation thereof will be omitted.

The difference is that, as shown in the perspective view of FIG. 2, the hexagonal column 10 is provided with a hexagonal truncated pyramid 11 having an inclined surface. Thereby, even if the hexagonal hole of the disk 7 and the hexagonal column 10 become unfitted, the original state can be smoothly restored.

In the above description, the hexagonal column 10 and the hexagonal hole of the disk 7 are fitted, but the hexagonal column is not necessary, and any polygonal column that can transmit the rotational force of the disk 7 to the shaft 9 may be used.

Effects of the Invention As is clear from the above-mentioned embodiments, according to the present invention, the pulley base fixed to the shaft is rotatably engaged, and a hole is formed to fit into a hexagonal column formed on the pulley base. A power transmission device for a magnetic recording/reproducing device in which a disc with a disc is fitted onto a pulley base at the hexagonal column position, and the rotational force of the pulley is transmitted to a shaft by the frictional force between the pulley and the felt attached to the pulley base and disc. Since a hexagonal truncated pyramid is provided on the end face of the hexagonal column, even if an unexpected force is applied to the pulley and the hexagonal hole in the disc cannot fit into the hexagonal column on the pulley base, it will return smoothly. , power can be reliably transmitted without the pulley spinning idly.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of an embodiment of the power transmission device of the magnetic recording and reproducing apparatus of the present invention, FIG. 2 is an enlarged perspective view of the main part of the same device, FIG. 3 is a cross-sectional view of a conventional example, and FIG. FIG. 5 is an enlarged perspective view of the main part of the device, and a sectional view showing the operation of the conventional example. 1...Rubber belt, 2...Pulley, 3
...Felt, 4...Pulley base,
5... Spring, 6... Felt, 7...
...Disc, 8...Cap, 9...
·shaft. Name of agent: Patent attorney Haruaki Koebi and 2 others! Commbell 1 Happy drawing number 1 Atsushi drawing

Claims (1)

[Claims] A pulley base having a shaft that transmits the rotational force of the motor to a mechanical part of the magnetic recording/reproducing device, a polygonal column fixed to the shaft and having a plane perpendicular to the shaft and a side edge parallel to the shaft, and a pulley base that is fitted with the polygonal column. a disc that is rotatably connected to the pulley base at a position sandwiched between the flat part of the pulley base, the felt attached to the disc, and the felt of the pulley base and the felt of the disc; It consists of a pulley whose outer periphery is driven by a rubber belt, and a spring that presses the disk toward the pulley base along the shaft.The friction between the felt and the pulley due to the pressing force of the spring transfers the rotational force of the pulley to the shaft. A power transmission device for a magnetic recording/reproducing device comprising a truncated polygonal pyramid arranged at the end of the polygonal column.